Software theft has been, and continues to be, pervasive. Individuals and companies typically try various techniques to combat software theft, including requiring a unique software key to install software, requiring online activation of software, requiring an active online connection to use software, encryption of software, and the like. Although these techniques typically prevent casual users from installing unauthorized copies, the techniques can typically be overcome by sophisticated users.
Another way to combat software theft is to try to identify the source of the stolen software using watermarks. This involves applying unique watermarks to each copy of the software so that when a stolen piece of software is found, the watermark in the stolen software will corresponding to one of the unique watermarks in the authorized software. This requires modification of the computer code, which is undesirable. Further, this technique can be overcome by removing the watermark from the stolen software or removing the watermark from the authorized software so that all further copies do not contain the unique watermark.